The present invention relates generally to airships containing lighter-than-air gas (hereinafter simply referred to as an "airship") and, more particularly, to a method of and apparatus for landing and anchoring such airships, including a method of and apparatus for propelling same.
Balloons, blimps and zepplins have captured the fancy of man since he first aspired to fly. These airships combine desirable characteristics from the standpoint of aerodynamics travel economy and ecology. Lighter-than-air vehicles can remain aloft indefinitely and are capable of touching down in areas which would be inaccessible for most other conventional transport vehicles. They can be powered by a simple propeller engine and refueling can be accomplished either directly from the ground or by means of a simple umbilical cord from another aircraft.
Airships containing lighter-than-air gas provide inexpensive and environmentally inoffensive means of transporting people or cargo. Unfortunately, rigid frame zepplins are virtually obsolete and, among currently utilized airships, blimps have been relegated to use for advertising and promotional campaigns while balloons find frequent use by fanciful dare-devils in attempted uncontrolled--and usually unsuccessful--record free-air flights.
People have been reticent since the later 1930's to pursue flight by lighter-than-air vessels, after the "Hindenburg" was mysteriously and spectacularly consumed by flames. However, with little modification of old designs--most notably through the use of inert helium gas rather than flammable hydrogen--the airship can be a most useful advance in the field of transportation. One disadvantage of most conventional airships is the awkwardness and expense associated with landing and anchoring them. In general, once the airships nears the ground, a large (about 10- to 25-man) ground crew is needed to "pull" the airship down to the ground by a plurality of cables which are lowered from the airship and to direct the nose of the airship into the anchoring mechanism. Thus, not only is the method of landing somewhat primitive, awkward and time-consuming, but also it involves substantial expense in the form of bulky anchoring structures, compensation for the ground crew, and a relatively lengthy landing approach area.
Moreover, the dangling cables from the airship are dangerous since they can touch high-power lines or get caught in trees and the like. Furthermore, such airships are incapable of truly vertical landing (i.e., without forward movement) unless the ground crew is pulling down the airship. In addition, the airship requires substantial land area for accommodating the landing approach for the airship, as well as for accommodating the airship, once anchored, if, as is the conventional method, the airship is to be free to swing by its nose around an anchoring structure secured to the ground. Thus, for example, with the airship moored by its nose, the circular land area required for mooring the airship has a diameter equal to about twice the length of the airship and the additional area for the approach will be even more.
One prior art patent, U.S. Pat. No. 1,567,703 issued to Broyles, discloses an anchoring assembly having an anchor which is lowered from the gondola and has electromagnets mounted therein. The anchor is suspended by a cable and winch assembly which enables the anchor to be lowered from the gondola and the airship to be pulled down by the winch once the electromagnets have magnetically engaged a suitable anchoring member on the ground. As a result of such anchoring, the airship is secured to the ground without any rotatable capability.
Although the anchoring device according to Broyles may operate satisfactorily from some applications, it does not enable rotation of the airship after it is anchored. In addition, while the airship is being "pulled down" by the cables, it would be completely at the mercy of the wind, and the cable could be chaffed during the winching operation. Moreover, any forces acting on the magnet/anchor via the cable, which are disposed in any direction other than vertical, would effectively cause a moment on the anchor, thereby tending to weaken the magnetic attraction between the magnet and the anchoring structure on the ground. Furthermore, lowering the magnet by the cables does not enable truly precision anchoring, and the cables could be twisted and snapped if the airship began rotating while being winched down. Also, it would probably be very difficult, if not impossible, for a pilot to attempt anchoring the ship while also having to control the airship simultaneously.
Although "heavy-lift" airships have been proposed for lifting heavy and/or bulky objects much like the "sky-crane" helicopter devices, conventional airships are not suitable for such applications without heavy ballast equipment. Once such airships have delivered their payload, the airship would, without the addition of substantial ballast, always tend to rise. Accordingly, there is a need for an improved airship which is capable of lifting and depositing heavy loads without requiring such additional heavy ballast equipment.
It is therefore an object of the present invention to provide new and improved anchoring means for airships containing lighter-than-air gas. Another object of the present invention is to provide new and improved propulsion means for use either alone or in conjunction with the anchoring means.
It is a further object of the present invention to provide a new and improved apparatus for landing and anchoring an airship, which enables landing and at least initial anchoring essentially by the pilot alone without the need for a ground crew or on-board help.
It is also an object of the invention to provide a new and improved airship having a simple and strong anchoring means, with the airship requiring relatively less land area than conventional techniques for approach, touchdown and anchoring.
It is yet a further object of the invention to provide an airship whose propulsion system can be located at various positions with respect to the longitudinal axis of the gas-containing structure for controlling the horizontal trim of the airship.
It is still another object of the present invention to provide new and improved propulsion means for a lighter-than-air airship, enabling the airship to lift and deposit heavy loads without requiring additional ballast equipment to enable the ship to descend after it is unloaded.
Objects and advantages of the invention are set forth in part above and in part below. In addition, these and other objects and advantages will be appreciated herefrom, or may be learned by practice with the invention, the same being realized and attained by means of the methods, apparatus and combinations pointed out in the appended claims. Accordingly, the invention resides in the novel structures, arrangements, steps and improvements herein shown and described.